Adjustable camshaft sprocket assemblies for internal combustion engines are well known and in widespread use. In general, the camshaft includes a camshaft sprocket assembly connected thereto that is driven by a chain or belt that is also engaged with a drive sprocket such as a crankshaft sprocket. The adjustable camshaft sprocket assembly allows for selective adjustment of the relative angular position between the camshaft sprocket and the camshaft to effect a corresponding timing adjustment of the intake and exhaust valves driven by the camshaft. Examples of such adjustable camshaft sprocket assemblies are disclosed in U.S. Pat. No. 6,532,923 and U.S. Pat. No. 5,174,169 and U.S. Pat. No. 5,495,776, all of which are hereby expressly incorporated by reference into the present specification.
In one common arrangement, the adjustable camshaft sprocket assembly is covered by a timing chain cover assembly that includes a main cover defining an access opening that is closed by a cap or lid. The lid of the timing chain cover assembly is removed as needed to provide access to the underlying camshaft sprocket assembly. U.S. Pat. No. 5,645,024 discloses an example of a timing chain cover of the type just described, and this patent is also hereby expressly incorporated by reference into the present specification.
It has been deemed desirable to provide a new and improved adjustable camshaft sprocket assembly that is also usable with a timing chain cover assembly such as disclosed in U.S. Pat. No. 5,645,024, wherein the angular position of the sprocket relative to the camshaft can be adjusted through the access opening of the timing chain cover assembly by removal of the lid, and without requiring the main timing chain cover to be removed. Also, it has been deemed desirable to provide an adjustable camshaft sprocket and tool for same, wherein the tool is simple and inexpensive to manufacture as compared to known designs, and wherein the adjustable camshaft sprocket assembly is simplified in construction and exhibits better overall performance.